Those wires are for the seatbelt pre-tensioners in your van (as well as the seatbelt reminder). The Pre-tensioners are an important safety feature. They take up seatbelt slack during a collision. If you remove the wiring, the pre-tensioners won't work, and you'll have the SRS light on all the time.

I always pull the SRS fuse (per the manual-I think Fuse #20??) and disconnect the starting battery (and separate the house batteries) to avoid triggering the SRS dash light when disconnecting the seat wiring connector; I'm concerned that my basic OBDII scanner may not be able to erase an SRS code.......